An extremely odd "twin," as pointed out by
contributor Dan Kurdilla, from Wyndmore, PA, is Lion Library LL2 and Tuxedo 124.
The Lion book appeared in 1954, the Tuxedo book in 1962. I am unaware of any
link between the two publishers. Dan points out that Martin Goodman, the man
behind Lion Books, was also heavily into publishing men's magazines, and may
have had something to do with adult-oriented books such as this, though that has not
been documented (as far as I can find).